The Good, the Bad, and the Ugly of ROS: New Insights on Aging and Aging-Related Diseases from Eukaryotic and Prokaryotic Model Organisms

Figure 7

Activities of potential importance for stasis-induced oxidation of proteins. Traditionally, increased protein oxidation has been argued to be an effect of (a) increased production of reactive oxygen species (ROS), presumably derived from respiratory activity, (b) diminished activity or abundance of the antioxidant systems, or (c) reduced activity of the proteolysis or damage repair systems. Work on E. coli has highlighted the role of some alternative pathways in protein oxidation. These pathways relate to the production of aberrant proteins, which are highly susceptible to oxidative modification (carbonylation). Increased levels of such aberrant, malformed polypeptides can be the result of (d) reduced translational fidelity, (e) reduced transcriptional fidelity, or (f) diminished activity of the repair refolding apparatus. In the early stages of E. coli growth arrest, reduced translational fidelity appears to be the most important contributing factor to the elevated levels of oxidatively modified aberrant proteins. E, core RNA polymerase; P^A, aberrant protein; P^N, native protein; P^ox, oxidized protein; T^A, aberrant transcript; T^N, native transcript. Reproduced with permission from Nyström, Thomas. “Aging in bacteria.” Current Opinion in Microbiology 5, no. 6 (2002): 596-601.